Occipital bone abnormality causing recurrent posterior circulation strokes

Abstract

We report the case of a young man with recurrent posterior circulation strokes over the course of 6 years. Standard stroke evaluation was unremarkable until careful review of catheter angiogram and CT angiogram images revealed a bony protuberance from the occiput impinging on the left vertebral artery. Local vessel injury with thrombosis and distal embolization is the presumed etiology of the recurrent infarcts. Surgical removal of this developmental anomaly was accomplished, with no subsequent neurological events.

Figure 1

Recurrent posterior circulation infarcts. A, Fluid-attenuated inversion recovery sequence from second presentation at age 20, showing all previous areas of infarction. B, Diffusion-weighted imaging from (i) second presentation at age 20; (ii) age 24; (iii) age 26; and (iv) age 26, 2 weeks later. All lesions are in the left vertebral artery distribution.

Figure 2

Imaging of vertebral arteries, C1, and occiput. A, Angiogram of left vertebral artery injection. Left, age 20; right, age 26. Arrow indicates area of vessel damage with fusiform widening seen on the later image. B, Preoperative coronal CT angiogram. Arrowhead indicates right vertebral artery course through C1 anomalous bony channel. Arrow indicates left vertebral artery with adjacent bony protuberance from the occiput. C, CT angiogram 3D reconstructions of the left vertebral artery course over C1. Removal of the occiput protuberance and vessel caliber normalization on 3-month postoperative image (right).